1. Field Of The Invention
This invention relates to a generally parallelepiped shipping container which is formed from a die-cut blank of a relatively rigid, foldable sheetlike material and which incorporates a self-locking top. This invention also relates to a die-cut blank of a relatively rigid, foldable sheetlike material from which such a shipping container can be formed. The preferred embodiment of this invention is a shipping container for fresh produce which can be provided with openings therein of substantial magnitude for good air circulation through the container.
2. Description Of The Prior Art
A generally parallelepiped or six-sided container of the type which is formed from a die-cut blank of a foldable, sheetlike material, for example, corrugated fiberboard, and which incorporates a self-locking feature, is shown in U.S. Pat. No. 3,272,421 (G. E. Perry). The aforesaid Perry patent discloses a six-sided container with such a self-locking feature at the bottom thereof. As is clear from this reference, the flaps at the bottom of the container which form the self-locking feature must be pushed a substantial distance into the interior of such container to engage one another in a self-locking manner. Thus, the self-locking feature of the container of this reference is suited for use with an empty container, but not for use with a container whose interior is filled with contents when the self-locking flaps are engaged. Further, the locking tabs of the locking flaps which extend into the interiors of the container are held flush with the other flaps which form the self-locking bottom by the weight of the contents which is placed therein. Thus, in a self-locking bottom, as opposed to a self-locking top, inherently the leading edge of the locking flap can not be jammed into the contents of the container. Further, yet the container of this reference is disclosed as being suited for the packaging of potato chips in polyethylene bags. Thus, this container does not incorporate the type of openings which are occasionally desirable in a container for fresh produce, such as grapefruit. In that regard, see U.S. Pat. No. 4,389,013 (Hall et al.) which shows ventilating openings in a fruit and vegetable produce container with a self-locking lid.
U.S. Pat. No. 3,294,221 (M. F. Notko et al.) describes a wardrobe container with a front panel which has an upper portion, and the upper portion is foldable to provide a hinged access door. A hanger bar is positioned near the top structure of this container, and this hanger bar is covered by a self-locking top which is engageable without being pushed a substantial distance into the interior of the container, an engagement technique that is precluded by the presence of the hanger bar. The self-locking top is formed by flaps at the top panels of the sides of the container, an opposed pair of such top flaps each having spaced apart locking tabs which are foldably attached along a scored or otherwise deformed line to a side flap which, in turn, is foldably attached to one of the opposed pair of side panels, one of which is the foldable portion of the front panel. The locking tabs, by virtue of their separation from the side flap to which they are joined, tend to bend at an oblique angle with respect thereto, and, thus, project into the interior of the Notko et al. container. This may not be a problem in a wardrobe container since the contents, garments, are probably suspended from hangers, and are not positioned close enough to the top of the container to be contacted, and possibly damaged, by the edges of the locking tabs which project into the interior of the container. However, this feature could be troublesome in a container with a self-locking top which is intended for the packaging of fresh produce, since the contents, which can be readily damaged, are usually positioned all the way to the top of the container. Thus, the contents of a fresh produce container can readily be contacted, and damaged, by the thin, leading edges of the locking tabs of a top structure like that of the Notko et al. container if they project obliquely into the interior of the container. Further, the top structure of the Notko et al. container is essentially imperforate, to prevent the entrance of dust and moisture into the container. Thus, such top structure lacks the type of openings which are occasionally desirable in a container for fresh produce.
U.S. Pat. No. 3,539,090 (R. O. Blasdell) also discloses a six-sided shipping container with a self-locking top. The locking tabs of the top flaps extend from flaps which are attached to the minor, or smaller, side panels, rather than the larger, or major, side panels as in the case of the Notko et al. container, and are also flexible with respect to interior portions of such flaps by virtue of the presence of scored or otherwise deformed lines, called "flexure creases" in the reference.